Defense starts for companies in Gulf spill trial

NEW ORLEANS (AP) -- The owner of the drilling rig that exploded at the outset of the 2010 Gulf of Mexico oil spill catastrophe started its defense Monday at a trial designed to determine the disaster's causes and assign fault to the companies involved.

Transocean Ltd. called its first witness — well control expert Calvin Barnhill — on the 13th day of the trial. Transocean president and CEO Steven Newman is scheduled to testify Tuesday.

U.S. District Judge Carl Barbier already has heard testimony by more than a dozen witnesses called by the Justice Department and attorneys for Gulf Coast businesses and residents who claim the spill cost them money. The plaintiffs' lawyers still expect to call another witness to the stand this week, an employee of cement contractor Halliburton.

Tranoscean's witnesses could take up the rest of the trial's fourth week. Halliburton and Macondo well owner BP PLC also will call their own witnesses after Transocean finishes presenting its case.

Barbier is hearing the case without a jury and — barring a settlement — could decide how much more money BP and its contractors owe for their roles in the catastrophe. BP could be on the hook for nearly $18 billion in penalties under the Clean Water Act if the judge finds that it acted with "gross negligence."

The explosion on the Deepwater Horizon rig in the Gulf of Mexico on April 20, 2010, killed 11 workers and led to the nation's worst offshore oil spill.

After a plaintiffs' expert finished testifying Monday, BP attorney Andy Langan asked Barbier to rule that the plaintiffs haven't proven the London-based oil giant acted with gross negligence or willful misconduct. Barbier said he wasn't ready to rule on that request yet.